The Liturgical books used in Orthodox worship fall into three main groups. The first of these are three books containing readings from Holy Scripture. These are the Book of Gospels, the Book of Epistles (Apostol), and the Book of Psalms (Psalter).

Book of Gospels.

This book contains the text of the four Gospels (Matthew, Mark, Luke and John) arranged in sections called pericopes (or zachalo in Russian). This book normally rests on the Holy Table, and is customarily treated in the same way as the Holy Icons, itself being regarded as an Icon of the Savior in His teaching ministry.

Book of Epistles (Apostol).

This contains the readings from the Acts of the Apostles and the Epistles for the whole year i.e., the entire New Testament outside of the Gospels and the Apocalypse (Revelation) of St. John. It too is divided into pericopes and also includes the Prokeimena and Alleluia verses which precede and follow the Epistle readings.

Book of Psalms (Psalter).

The Psalter contains the 150 Psalms of David, divided into twenty Kathismas, as well as the text of the Nine Biblical Canticles sung at Matins.

The Kathismas are here divided into their respective Stases or divisions. They are numbered according to the Hebrew rendering. The Septuagint (LXX) divisions are to be found within the parentheses.

The Old Testament lessons, usually read at Vespers, are not normally found in a separate book. These are usually found in appropriate sections of the Triodion, Pentecostarion or Menaion, as the case may be.

The next grouping of Liturgical books are those pertaining to the fixed parts of the services, which usually do not change according to the season or Saint. Among these are the Euchologion and the Book of Hours.

Euchologion.

The Euchologion (or Book of Prayers) is for the use of the Priest and Deacon and contain the Sacraments and other services, as well as many special prayers and blessings. The Euchologion is usually divided into several books:

Great Euchologion.

This contains the fixed parts of Vespers, Matins and the Liturgy (primarily the Priest's parts), the six remaining Sacraments (Baptism, Chrismation, Holy Orders, Confession, Marriage, Anointing of the Sick), and other services (Monastic Profession, Consecration of a Church, Blessing of Waters, etc.).

Priest's Service Book. (Greek Ieratikon; Russian Sluzhebnik).

This is an Altar Book containing primarily the Priest's parts at Vespers, Matins and the Divine Liturgy.

Book of Needs. (Russian Trebnik).

This book contains five of the Sacraments (the Divine Liturgy and Holy Orders are omitted), the Funeral Service, and various other services commonly used.

Pontifical Service Book. (Greek Archieratikon; Russian Chinovnik).

This is a special book of prayers and blessings used by the Bishop.

Book of Hours.

The Great Book of Hours (Greek Horologion) is a Choir book for the use of the Reader and Singers. It contains the fixed portions of the Daily Offices (Vespers, Matins, etc.) with most of the Priest's and Deacon's parts omitted. It also contains a list of Feasts and Saint's days throughout the year as well as appropriate Troparia and Kontakia for each. In addition there is a section containing Troparia and Kontakia for Sundays and movable Feasts of the period of the Triodion and Pentecostarion, as well as Theotokia for the whole year. There are also contained in this book various Canons and other services in frequent use. In the Russian Church, there is also an abbreviated form of the Great Book of Hours, called simply the Book of Hours (Russian Chasoslov).

For the movable parts of the services (those which change every day) there are four volumes constituting the three main cycles of the Church Year: 1) the Weekly Cycle Octoechos; 2) the Annual Cycle of Movable Feasts Triodion and Pentecostarion; and 3) the Annual Cycle of Fixed Feasts the Menaia.

Octoechos.

The Octoechos (or Book of the Eight Tones) contains the movable parts of the Daily Offices sung throughout the week. Eight series of Offices, one for each of the Eight Tones, are provided, within which are seven sets of services, one for each day of the week. The First Tone begins on St. Thomas Sunday and proceeds in sequence each week until Tone Eight is completed, at which time the whole cycle is repeated. The texts of the Octoechos are combined, more or less, with fixed Feasts from the Menaia, and on Saturdays and Sundays during Great Lent (except from Lazarus Saturday to the Sunday of All-Saints).

Triodion.

This book, characterized by its extensive use of Three-Ode Canons (although there are also some Four-Ode Canons contained within), is generally termed the Lenten Triodion, within which are found the Texts for the services of Great Lent.

Pentecostarion.

This companion to the Lenten Triodion (often called the Flowery Triodion) contains the texts from Pascha to the Sunday of All-Saints (the first after Pentecost).

Menaia.

This book is divided into twelve volumes (corresponding to the twelve months) and contains the texts for the fixed Feasts of each day of the year. In addition, there is sometimes found two companion volumes which contain certain texts from the major Fixed Feasts (the Festal Menaion) or general Offices for certain classes of Saints (the General Menaion).

In addition to these three main groups of liturgical books, there are two further books the Irmologion and the Typikon.

Irmologion.

This book gives the texts of all of the Irmosi (or Theme Songs) sung at the beginning of the various Canticles of the Canon. Often some editions of the service books, such as the Menaia and Triodion, only give the opening words of the Irmos, necessitating the use of the Irmologion, which provides the full texts.

Typikon.

This book contains the rules and rubrics governing every aspect of the Church services and their celebration throughout the year. According to Church Tradition, the Typikon was drawn up by St. Sabbas of Jerusalem (f532) and later revised by St. Sophronius, Patriarch of Jerusalem (tea.638). A further revision was made by St. John of Damascus (tea.749), a Monk at St. Sabbas' Monastery, hence the name the Jerusalem Typikon of St. Sabbas' Monastery.

In 1888, a new edition of the Typikon was prepared at Constantinople, which, in modern times, is used primarily by the Greek-speaking Churches. The Church of Russia, as well as, for the most part, the Orthodox Church in America, still adheres to the Jerusalem Typikon, as do the older Greek monasteries, such as those of Mt. Athos, St. Sabbas at Jerusalem, and St. John on Patmos.

Excerpt taken from "These Truths We Hold - The Holy Orthodox Church: Her Life and Teachings". Compiled and Edited by A Monk of St. Tikhon's Monastery. Copyright 1986 by the St. Tikhon's Seminary Press, South Canaan, Pennsylvania 18459.